nl

A utility for numbering lines, either from a file, or from stdin. More information: https://www.gnu.org/software/coreutils/nl.

• Number non-blank lines in a file:
  nl {{path/to/file}}
• Read from stdout:
  cat {{path/to/file}} | nl {{options}} -
• Number only the lines with printable text:
  nl -t {{path/to/file}}
• Number all lines including blank lines:
  nl -b a {{path/to/file}}
• Number only the body lines that match a basic regular expression (BRE) pattern:
  nl -b p'FooBar[0-9]' {{path/to/file}}